Device for delivering fluids under pressure



Oct. 25, 1932. w. POOL 1,88 ,8

DEVICE FOR DELIVERING FLUIDS UNDER PRESSURE Filed Feb. 11. 1928 Patented Oct. 25, 1932 UNITED STATES PATENT OFFICE.

WILLIAM. POOL, F CBAYFORI ENGLAND, ASSIGNOB, BY MESNE ASSIGNMENTS; TO BRITISH CELANESE LIMITED, OF LONDON, ENGLAND, A COMPANY OF GREAT BRITAIN DEVICE FOR DELIVERING FLUIDS UNDER PRESSURE Application filed February 11, 1928, Serial No. 253,652fand inGreat Britain May 16, 1927.

This invention relates to devices for delivering fluids under pressure, of the kind inwhicha pump (preferably of the gear type) is supplied with fluid under pressure and is associated with means for maintaining equal pressures betweenthe inlet and delivery sides of' the pump irrespective of variations in the delivery pressure, so that the pump acts in effectas a meter which delivers a volume of fluid dependent only on the capacity. or output of the pump thereby eliminating losses which would Otherwise occur due to slip or leakage past the moving parts of the pump.

According to the-invention I provide between the conduit'supplying high pressure fluid to the pump and the inlet port of the latter-a reducing valve which is acted upon by the reduced pressure at the inlet side of the pump and the pressure at the delivery side of the said pump and which serves to increase the extent of its opening when the delivery pressure increases beyond the re duced pressure at the inlet side of the pump when the delivery pressure falls below the pressure on the inletside; the amount of the increase or decrease being sufficient to restore the balance between-thereduced inlet pressure and thedelivery pressure. valve may furthermore operate to place the inletandadelivery sides of the pump in communication'with each other. in the event of thewdelivery pressure exceeding the pressure in the high pressuresupply conduit, thereby shortscircuiting theapump which is then, in effect, thrown out of action, the said valve at the same time shutting off the high pressuresupply to the inlet side of the pump.

In order that the said invention may be clearly understood and readily carried into effect, the same will now be more fully described with reference to the accompanying 3 drawing in which Figure 1 is a sectional elevation showing andto decrease-theextent of its opening The said in another position hereinafter referred to,-

the same, the saidpump A will act as a meter to deliver a volume of liquid dependent only on its capacity or-output, the losses which would. otherwise occur-due to slip or leakage past the moving parts of the pump A being thus avoided. B is the reducing valve con* tained in a casing B1 whichhas an inlet port B communicating with a supply main B for the high pressure fluid and an outlet-B for the fluid delivered by the pump A, this outlet being in constant communication with the aforesaid delivery pipe A through a port B The said valve casing also has a reduced pressure outlet port B communicating with the inlet pipe A In the construction shown the valve B is of the sliding pistontype having in its circumference two annular grooves 22, b forming three bands 6 b 6 on the valve. The upper face of this valve is subjected to the reduced pressure in the inlet pipe A through holes 6", -and the lower face is subjected to the pressure in the delivery pipe A these two pressures normally balancing one another. Theupper band 6 serves to control the passage of fluid from the high pressure supply port 13 to the inlet pipe of the pump, the fluid passing through the said holes 6", which establish communication between the two annular grooves b, 6 these holes also extend to the upper face of the valve contiguous to the high pressure supply port B so that the reduced inlet pressure acts on this face as aforesaid. The supply fluid in the main B is at a pressure equal to the maximum pressure likely to be experienced at the delivery side of the pump (i. e. in the pipe A and may be obtained from a suitable supply pump. Normally the high pressure supply port B is slightly opened by the upper band 5 of the valve B as shown in Figure 1 to give a reduced pressure-in the inlet pipe A of the pump equal to the' normal delivery pressure in the pipe A and the outlet B and the valve is therefore in a state of balance; it the latter pressure should rise, the valve moves upwards to open the high pressure supply port l3 further so as to admit more high pressure supply fluid until the valve is again in a state of balance; whilst'if the said delivery pres sure should fall, the valve moves downwards towards t-he'clos'ed position soas to admit less .high pressure supply fluid until a balanced s'tate'is once more reached. The valve casing B isformed' with an annular recess b in constant communication with the inlet conduit B tothe pump, which recess is normally covered by the loWer band b of the valve, but is uncovered as shown in Figure 2 when the Valve moves to the'upper end of its travel as a result of increase of the delivery pressure in the pipe A and outlet B beyond the pressure of the supply'in the main B this uncovering of the annular recess establishing communication between the inlet and delivery pipes A A of the pump so as to short-circuit the latter; at the same time the middle band?) of the valve closes the high pressure supply port B Delivery of the fluid is consequently completely stopped. and.

- the latter operations the valve first falls by gravity, and then when the middle band 6 uncovers the high pressure supply port B the valve is moved downwards by the pres sure acting on the upper face of the valve. When the latter reaches its lowest position the upper band 79 cuts otl the high pressure supply as shown in Figure 3. obstruction tothe delivery is cleared and the pump A: again started, the suction of the said pump in the inlet pipe A raises the valve slightly thus uncovering the high pressure supply port B High pressure fluid then enters the valve casing and the pressure balance between the inlet and delivery sides of the pump A is then established as above described.

The invention is particularly intended for supplying cellulose acetate or other cellulose solution to extruding heads for the formation of artificial silk threads and in this case there 'is one pump-like element and valve as described above for each extruding head and all the pumps are preferably supplied with the solutiontrom a common supply main into which a single pump delivers hen the the solution at high pressure. The usual pressure in the supply main will be about from 1000 to 1500 lbs. per square inch, and the pressure in the delivery will vary from about 40 lbs. per square inch upwards according to the resistance of the filters and other parts.

What I claim and desire to secure by Letters Patent ot the United States is 1. Pumping apparatus for delivering fluids under pressure, comprising a high pressure conduit, a pump, and a reducing valve interposed in series between said high pressure conduit and said pump, said reducing valve having an inlet port communicating with said high pressure conduit and a port communicating between the low pressure side of said reducing valve and the inlet side of said pump and a port communicating with the delivery side of the pump, a moving member subjected on its respective .opposite sides to the pressure of the inlet side of the pump and to the pressure of the delivery side of the pump, and a valve member connected to said moving member and arranged to control the inlet port of said reducing valve; whereby the supply of fluid from the high pressure conduit to the pump is controlled and equal pressures are maintained as between the inlet and delivery sides of the pump as long as the pressure on the delivery side thereof does not exceed the pressure of the high pressure conduit,,characterized by a communication between the inlet side of the pump and its delivery side, the moving member of the reducing valve being adapted to keep said communication closed under normal conditions of operation, but to open said communication when the delivery pressure of the pump eX- ,7

ceeds the pressure of the high pressure conduit, said moving member being further adapted to operate the valve member to close the inlet portcommunicating with the high pressure conduit when the pressure of the delivery side of the pump rises in excess of the pressure of the high pressure conduit.

2. Pumping apparatus for delivering fluids under pressure, comprising a high pressure conduit, a pump, and a reducing valve interposed between said high pressure conduit and said pump, said reducing valve comprising a bored casing having an inlet port communicating with said high pressure conduit, a port communicating between the low pressure side of said reducing valve and the inlet side of the pump and a port communicating with the delivery side of the pump, a moving piston member operating in the bore of said casing and subjected on its respective opposite sides to the pressure of the inlet side of the pump and to the pressure of the deliveryv side of the pump, said moving member being arranged intermediate between the port in communication with the inlet side of the pump and the port in communication with the delivery side of the pump a valve member connected to said moving piston member and comprising two bands operating in the bore of said casing under the action of said moving member, said bands having an annular groove between them and a passage in each communicating between said annular groove and the interior of said bored casing, said valve member being adapted to control the inlet port of said reducing valve by the positioning of said annular groove relatively to said inlet port under the action of said moving member 5 whereby the supply of fluid from the high pressure conduit to the pump is controlled and equal pressures are maintained as between the inlet and delivery sides of the pump as long as the pressure on the delivery side thereof does not exceed the pressure of the high pressure conduit.

3. Pumping apparatus according to claim 7, characterized by the casing having a recess formed in its bore and communicating with the port in said casing communicating with the inlet side of the pump, the moving piston member being adapted to cover said recess under normal conditions of operation, and to uncover said recess when the pressure of the delivery side of the pump rises in excess of the pressure of the high pressure conduit, thereby establishing communication between said recess and the port in communication with the delivery side of the pump through the bore of said casing and thereby short circuiting the pump, said moving piston member being further adapted to operate the valve member to close the inlet port communicating with the high pressure supply conduit when the pressure of the delivery side of the pump rises in excess of the pressure of the high pressure conduit.

WILLIAM POOL.

CERTIFICATE 0F GORREGTW'N.

Patent No. 1,884,852. Oeteher 25, 1932.

WILLIAM POOL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as feliews: Page 2, iine 61, strike out the hyphen and words "-like element"; page 3, line 21, claim 3, for "7" read "2"; and that the said Letters Patent sheuiti be read with these corrections therein that the same may ceniorm to the reeerd at the case in the Patent Office.

Signedand sealed this 27th day of December A. D. 1932.

M. J. Moore,

(Seal) Acting Gemmissioner of Patents. 

